Graphics card apparatus with improved heat dissipating mechanisms

ABSTRACT

A cooling mechanism to dissipate thermal energy generated by the active electronic components of a graphics card assembly. A mechanism includes a radiator and a metal block that is thermally coupled to the active electronic components and that has a tubing therewithin. The radiator includes a pipe and baffles attached to the pipe, where one end of the pipe is connected to one end of the tubing. A pump, connected to the other ends of the tubing and pipe, circulates coolant through the pipe and tubing to transfer thermal energy from the metal block to the radiator. The mechanism also includes a heat sink that is thermally coupled to the metal block via a thermal transfer plate. A fan unit of the mechanism generates and directs an air flow toward the radiator, metal block and heat sink, where the air flow removes the thermal energy therefrom.

BACKGROUND OF THE INVENTION

The present invention generally relates to graphics card apparatus and, more particularly, to an improved graphics card assembly having a cosmetic cover plate and two heat dissipating mechanisms cooled by a fan unit.

In order to enable desktop and other computers to rapidly process graphics and game technology, add-on units generally referred to as “graphics cards” or “VGA” cards” are often installed in computer devices. Such cards include a separate processor, called a GPU, one or more memory chips, and other required circuitry, all mounted to a circuit board including an edge connector that is adapted to plug into an available slot in the associated computer device.

Such cards often have extremely large computing power and, as a consequence, generate substantial heat that if not dissipated will adversely affect operation of the graphics card. Heretofore, various approaches have been tried to dissipate or otherwise remove heat from the thermal energy generating components and normally include some type of fan for blowing air across the active components, and perhaps some type of thermal mass capable of sinking the heat generated. To date, however, the efficiency of such devices has not been optimal. Besides, the thermal energy generated by the GPU and memory chips for more sophisticated graphics and games, such as 3-D graphics, may approach the maximum capacity of the existing heat dissipation mechanisms. Thus, there is a need for an improved heat extraction or dissipation mechanism, which can be added to a standard graphics card to efficiently remove thermal energy generated thereby.

SUMMARY OF THE INVENTION

The present invention provides a graphics card assembly that has two heat dissipating mechanisms or subassemblies to dissipate thermal energy generated by active electronic components, such as GPU and memory. The first mechanism includes a heat sink that is thermally coupled to the electronic components and that has one or more radiators, where the thermal energy transferred to the heat sink is dissipated by a portion of air flow generated by a fan. The second mechanism includes a metal block that has a tubing therewithin and a radiator that has baffles and a pipe. The metal block is thermally coupled to the heat sink of the first mechanism and receives any thermal energy that is not dissipated by the first mechanism and thus remaining in the heat sink. A pump, connected to the pipe and tubing, circulates coolant therethrough so that the thermal energy conducted to the metal block is sunk to the baffles of the radiator. A portion of air flow generated by the fan is directed toward the metal block and radiator to remove heat therefrom.

In one aspect of the present invention, a graphics card apparatus with improved heat dissipation includes a radiator and a metal block that is thermally coupled to one or more active electronic components of the apparatus and that has a tubing therewithin. The radiator has a pipe and baffles thermally coupled to the pipe, where the inlet end of the pipe is connected to the exit end of the tubing. A pump, connected to the inlet end of the tubing and the exit end of the pipe, circulates coolant through the pipe and tubing to transfer thermal energy from the metal block to the radiator. The apparatus also includes a fan carrier for carrying a fan and vanes, where the air flow generated by the fan is directed toward the radiator baffles and metal block by the vanes. A flow director is positioned beneath the cover plate of the apparatus and surrounds the radiator and metal block forming an air flow passage from the fan to the metal block and thence to the radiator. Thermal energy generated by the electronic components is transferred to the metal block and thence to the radiator via the coolant and is ultimately removed from the radiator and metal block by an air flow drawn into the air passage.

In another aspect of the present invention, a graphics card assembly includes a printed circuit board with heat generating components affixed thereto and a heat dissipating mechanism attached to the printed circuit board. The heat dissipating mechanism includes a radiator and a metal block that is thermally coupled to the heat generating components and that has a tubing therewithin. The radiator has a pipe and baffles thermally coupled to the pipe, where the inlet end of the pipe is connected to the exit end of the tubing. A pump, connected to the inlet end of the tubing and the exit end of the pipe, circulates coolant through the pipe and tubing to transfer thermal energy from the metal block to the radiator. The mechanism also includes a fan carrier for carrying a fan and vanes, where the air flow generated by the fan is directed toward the radiator baffles and metal block by the vanes. A flow director is positioned beneath the cover plate of the assembly and surrounds the radiator and metal block forming an air flow passage from the fan to the metal block and thence to the radiator. Thermal energy generated by the components is transferred to the metal block and thence to the radiator via the coolant and is ultimately removed from the metal block and the radiator by an air flow drawn into the air passage.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a presently preferred embodiment of a graphics card assembly including an upper and a lower heat dissipating mechanism in accordance with the present invention;

FIG. 2 is an exploded perspective view showing the several components of the lower heat dissipating mechanism, fan carrier, flow director and middle plates included in the graphics card assembly illustrated in FIG. 1;

FIG. 3 is an exploded perspective view showing the several components of the upper heat dissipating mechanism and flow director included in the graphics card assembly illustrated in FIG. 1;

FIG. 4 is a side elevation taken along the direction 4-4 of FIG. 1;

FIG. 5 is an assembly view shown in plan form with the cover plate, upper heat dissipating mechanism, middle plates and thermal transfer block partially broken away to reveal the internal detail of the lower heat dissipating mechanism;

FIG. 6 is an assembly view shown in plan form with the cover plate broken away to reveal the internal detail of the upper heat dissipating mechanism; and

FIG. 7 is a perspective view of the thermal transfer block depicted in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

Referring to FIG. 1 of the drawing, a graphics card assembly in accordance with the present invention is illustrated at 10 and includes a lower heat dissipating mechanism 11 and an upper heat dissipating mechanism 13. As illustrated, the assembly also includes a printed circuit board 12 having edge connectors 14 and populated with numerous electronic components some of which are shown at 16. The board is attached at the near end to an end plate 18 carrying various cabling connectors 20, 22 and 24 used to communicate signals into and out of the assembly. The end plate 18 also has perforations or holes 21 forming the inlet of air flow generated by a fan unit, as will be explained later. Affixed to the printed circuit board 12 by means of vertically extending spacing legs or risers, one of which is shown at 26 c, is a planar, generally rectangular middle insulating plate 32. The cover plate 40 is secured to the board 12 and insulating plate 32 by means of risers, two of which are shown at 26 a and 38. The cover plate 40 may be made of a heat conducting material, while the insulating plate 32 may be made of Teflon or any suitable heat insulating plastic. The thermal transfer plate 30 has a generally rectangular shape and a side that is in contact with the insulating plate 32. The foremost extremity of the cover plate 40 includes a laterally extending tab 34 conforming to a similar tab on the board 12.

The front edge of the cover plate 40 is captured beneath a turned back lip 48 forming a side of the cover plate 40. Disposed between the plate 40 and plates 30 and 32 is the upper heat dissipating subassembly 13 including an upper heat sink or radiator, a metal block and a portion of a flow director 42, which will be elucidated below. Note that the cover plate 40 is flat and ideally suited for decorative graphics, manufacturer's or marketer's trademarks, etc. A lower heat sink 36 is affixed to the board 12 by means of vertically extending risers (not shown in FIG. 1).

In use, the graphics card assembly is oriented so as to have the near right edge of the assembly, as depicted, facing a slot on a computer motherboard and mounted thereto by slipping the edge connectors 14 into the slot so that the assembly communicates with devices on the motherboard via the edge connector 14. As described in more detail below, most of the thermal energy generated by the electronic components of the assembly is sunk to the lower heat sink 36 and upper radiator (not shown in FIG. 1), wherein the lower heat sink 36 and upper radiator are cooled by the air flow created by a fan unit 29 (not show in FIG. 1).

In FIG. 2, the lower heat dissipating mechanism 11, fan unit 29 carried by a fan carrier 35, middle plates 30 and 32, risers 26 a-26 c, and flow director 42 are shown exploded away from the populated graphics card 12. The lower heat dissipating mechanism 11 (FIG. 1) includes: the lower heat sink 36 that has a Zalman tube 86 and heat sinks or radiators 37 and 39; additional heat sink ribs or radiator 88; and thermal transfer block 56. The lower heat dissipating mechanism 11 also includes copper plates 50, 52 and 54 that are shown below the lower heat sink 36 and radiator 88. The plates 50, 52 and 54 may be formed of any suitable material that has good heat conducting characteristics. These copper plates 50, 52 and 54 respectively engage the top surfaces of and transfer heat from GPU, memory and power IC that are not shown but will be positioned at 60, 62 and 64 on the board 12. Each of the copper plates 50, 52 and 54 may be soldered or brazed to, or molded into the bottom of the lower heat sink 36 or radiator 88. The thermal transfer block 56 engages the top surface of a heat generating, active electronic component that is not shown but will be positioned at 58, and transfer heat to the middle thermal transfer plate 30.

The fan carrier 35 includes a top plate 63, a bottom plate 67, a side wall 43 and a flow barrier 65, and encloses the lower fan unit 29. The bottom plate 67 carries the fan unit 29 and vanes 87 for directing the air flow generated by the fan toward the lower heat sink 36. The bottom plate 67 also includes a circular hole (not shown in FIG. 1) for accommodating the fan unit 29. The top plate 63 has a circular aperture or hole 31 through which the fan unit 29 draws air. The holes 21 in the end plate 18 provide fluid communication between the atmosphere and circular aperture 31. The lower heat sink 36 includes a generally flat bottom plate and radiators 37 and 39 formed on the bottom plate, wherein the bottom plate and radiators are made of materials having good heat conducting characteristics.

Thermal energy generated by electronic components, such as GPU and memory, is transferred to the lower heat sink 36 via the plates 50 and 52. A portion of the air flow, which is generated by the fan unit 29 and passes through the radiators 37 and 39, tends to remove the thermal energy as it propagates through the copper blocks 50 and 52 to the top of the radiators 37 and 39. The thermal energy remaining in the radiators 37 and 39 is transferred to the thermal transfer plate 30 that is soldered or brazed to the top of the radiators 37 and 39.

The fan carrier 35 is attached to the flow director 42. Alternatively, the flow director 42 and the fan carrier 35 are formed in one body. The middle thermal transfer plate 30, preferably made of copper, is attached to the top edges of the radiators 37 and 39. As pointed out above, the copper plates 50 and 52 affixed to the bottom surface of the lower heat sink 36 engage the top of the GPU and memory to be mounted at 60 and 62, respectively, in order to transfer heat therefrom to the lower heat sink 36. As will be explained in more detail, any thermal energy remaining in the radiators 37 and 39 is conducted to the metal block of the upper heat dissipating assembly 13 via the thermal transfer plate 30.

The height of the thermal transfer block 56 is such as to substantially span the distance between the top of a corresponding active component mounted to board 12 and the bottom surface of the thermal transfer plate 30. Any gap remaining is closed by an appropriate thermally conductive compound. Likewise, any gap between the bottom surface of the metal plates 50 and 52 and the top of active electronic components is closed by an appropriate thermally conductive compound. The lower heat sink 36 is secured to the board 12 by a force fit of the upper ends of four risers 26 b to openings 69 in the heat sink 36. The lower ends of the risers 26 bare secured to the board 12 by means of appropriate mounting screws 68 or other suitable fasteners. Alternatively, the lower heat sink 36 and the bottom plate 67 may be formed in one body.

As will be illustrated later, the middle insulating plate 32 prevents the air flow passed through the lower heat sink 36 from heating an upper radiator (not shown in FIG. 2) positioned over the plate 32. The plate 32 is secured to the board 12 by a force fit of the upper ends of three risers 26 c to openings 80 in the plate 32. The lower ends of the risers 26 c are secured to the board 12 by mounting screws 78 or other suitable fasteners. As will be explained in FIG. 3, the cover plate 40 is secured to the board 12 by the same way as the plate 32 using the two risers 26 a and the screws 74.

As the GPU and memory of the recent graphics cards may generate thermal energy exceeding the maximum capacity of the lower heat dissipating mechanism 11 depicted in FIG. 2, an additional cooling mechanism may become necessary. FIG. 3 shows an exploded view of the additional cooling mechanism, referred to as upper heat dissipating mechanism 13 (FIG. 1), middle plates 30 and 32, risers 38, flow director 42, fan carrier 35 and cover plate 40. The upper heat dissipating mechanism 13 includes: an upper heat sink or radiator 94 including a pipe 92 and baffles thermally coupled to the pipe; a metal block 96; and a pump 102. The pump 102, such as a Ceramic pump, circulates coolant through the pipe 92 and a tubing 98 formed in the metal block 96 to transfer thermal energy in the metal block 96 to the radiator 94. The thermal transfer plate 30 transfers any thermal energy remaining in the lower heat sink 36 (FIG. 2) to the metal block 96. The metal block 96, preferably made of copper, includes a hollow tubing or tortuous flow passage 98 for circulating coolant therethrough, and secured to the flow director 42 by four screws 126 passed through openings 100 on the flow director 42 and threaded into threaded bores tapped into the sides of the metal block 96.

The upper radiator 94, including baffles and the pipe 92 attached to the baffles, is secured to the flow director 42 by four screws 124 passed through the openings 125 in the flow director 42 and threaded through threaded bores (not shown in FIG. 3) tapped into sides of the upper radiator 94. The upper radiator 94 has a structure similar to the radiator 88, i.e., it has a bottom plate and baffles formed on the bottom plate. Alternatively, the upper radiator 94 may be molded onto the flow director 42. Further alternatively, the upper radiator 94 may include a portion of the pipe 92 and baffles only. The pipe 92 is connected to the tubing 98 and the pump 102 forming a closed passage of coolant circulated by a pump 102, and thereby the thermal energy in the metal block 96 is transferred to the radiator 94 via the coolant.

The height of the flow barrier 65 is such as to maintain a predetermined distance between the top plate 63 of the fan carrier 35 and cover plate 40, where the predetermined distance is at least 5 mm in the preferred embodiment. As mentioned, the fan carrier 35 is molded onto the flow director 42 or attached to the flow director 42 by a suitable method, such as soldering. The flow director 42 having a generally elongated strip shape is secured to the cover plate 40 by four screws 114 passed through openings 116 and threaded into threaded bores 118 tapped into the flow director 42. The flow director 42 and cover plate 40 form an enclosure providing an air passage therebetween so that a portion of the air flow generated by the fan unit 29 passes over the metal block 96 and through the upper radiator 94 dissipating heat in the metal block 96, pipe 92 and radiator 94. The insulating plate 32 prevents heat transfer between the upper radiator 94 and the air flow passed through the lower heat sink 36 (FIG. 2).

As the air flow removes thermal energy from the metal block 96 and upper radiator 94 as it passes through the air passage, the air temperature is highest at the downstream end of the passage, i.e., at near the right hand side edge of the upper radiator 94. Thus, the efficacy of the upper heat dissipating mechanism 13 may be maximized by positioning the hottest portion of the pipe at the downstream end of the passage. As depicted in FIG. 3, the coolant exiting from the exit port of the pump 102 enters into the inlet end of the tubing 98 and removes thermal energy from the metal block 96. The temperature of the coolant reaches the highest point when the coolant exits from the outlet end of the tubing. Subsequently, the heated coolant is directed toward the downstream end of the air passage through the pipe 92 and cooled down as it passes through the upper radiator 94 and returns to the pump 102.

The insulating plate 32 is secured to the cover plate 40 by a force fit of the lower ends of three risers 38 to openings 80 in the insulating plate 32. The upper ends of the risers 38 are secured to the cover plate 40 by mounting screws 106 (or other suitable fasteners) that pass through the holes 110 in the cover plate 40. The cover plate 40 is secured to the board 12 by risers 26 a, where the top ends of risers 26 a are secured to the cover plate 40 by a force fit and the bottom ends of risers 26 a are secured to the board 12 by mounting screws 74 (FIG. 2)

In FIGS. 2 and 3, only two radiators 37 and 39 and one heat transfer block 56 are shown to transfer heat to the upper heat dissipating mechanism 13 via the thermal transfer plate 30. However, it should be apparent to those of ordinary skill that more or less radiators or heat transfer blocks may be used without departing from the essence of the present invention.

FIG. 4 is a side elevation of the graphics device assembly 10 taken along the direction 4-4 in FIG. 1, illustrating air flows through the lower and upper heat dissipating mechanisms 11 and 13. The fan unit 29 draws air through the opening 21 in the end plate 18 and thence through the circular aperture or hole 31 in the top plate 63 of the fan carrier 35. The air flow 97 a generated by the fan unit 29 is split into upper and lower air flows 97 c and 97 b. The upper air flow 97 c passes through the air passage formed by the cover plate 40 and flow director 42 dissipating heat from the heat block 96 and upper radiator 94 (FIG. 3), and exits the upper heat dissipating mechanism 13. The lower air flow 97 b passes through the lower heat sink 36, radiator 88 and thermal transfer block 56 (FIG. 2), and is discharged to open space around the electrical components 16. The insulating plate 32 prevents the lower air flow 97 b passed through the lower heat sink 36 from heating the upper radiator 94 (FIG. 3).

In FIG. 5, an assembled card apparatus 10 is shown from the top with the cover plate 40 and middle plates 30 and 32 partially broken away to reveal the fan carrier 35 having vanes 87, lower heat sink 36 and thermal transfer block 56. As pointed out above, thermal energy generated by GPU and memory (not shown in FIG. 5 but will be mounted to the board 12) is conducted into the bottom of the lower heat sink 36 and thence to the radiators 37 and 39 which in turn transfer heat to the plate 30 (FIG. 3). The lower air flow 97 b generated by the fan unit 29 is directed through the radiators 37 and 39, drawing with it the heat transferred from the bottom plate of the lower heat sink 36, the radiators 37 and 39, and the bottom surface of the thermal transfer plate 30, and thence discharged to the space around the radiator 88, thermal transfer block 56 and other electronic components 16.

Alternatively, the fan unit 29 could be reversed to draw air in from the open sides of the lower heat dissipating mechanism 11 through the radiators 37 and 39 and to discharge the heated air through the holes 21 (FIG. 2) in the end plate 18. Flow in this direction would be preferable for some applications where the thermal energy generated by the thermal transfer block 56 and radiator 88 is substantially less than the thermal energy generated by the GPU and memory.

In FIG. 6, an assembled card apparatus 10 is shown from the top with the cover plate 40 partially broken away to reveal the fan unit 29, vanes 87, upper radiator 94, metal block 96, flow director 42, cooling pipe 92, pump 102 and middle plates 30 and 32. The upper air flow 97 c generated by the fan unit 29 is directed through the air passage formed by the cover plate 40 and flow director 42; it passes over the metal block 96 and through the baffles of the upper radiator 94, drawing with it the heat transferred to the metal block 96, pipe 92 and upper radiator 94 before it is discharged to the open space on the right hand side of the assembly 10. Suitable coolant is circulated through the pipe 92 and tubing 98 by the pump 102 so that the heat transferred to the metal block 96 is transferred to the upper radiator 94. Alternatively, the fan unit 29 could be reversed in some applications where the temperature of the upper radiator 94 is substantially lower than the temperature of the metal block 96. Further alternatively, an additional thermal transfer plate (similar to the plate 30) may be positioned between the upper radiator 94 and the cover plate 40 made of a heat conducting material, where the additional thermal transfer plate transfers heat from the upper radiator 94 to the cover plate 40.

FIG. 7 is an exemplary form of a simple thermal transfer block that may be uses as the thermal transfer block 56 in FIG. 2. The block may be formed of, preferably, copper metal. However, any material having good thermal conductivity may be used. The illustrated block has four elongated openings 82 for receiving air flow induced by the fan unit 29 (FIG. 6). The bottom surface 86 is planar and intended to physically engage the top surface of an active electronic component mounted on the board 12 and transfer thermal energy therefrom. Similarly, the top surface 84 is planar and intended to engage the bottom surface of the thermal transfer plate 30 either directly or via an appropriate heat transferring compound deposited therebetween. Air flowing through the openings or passageways 82, as well as around the sides of the block, tends to remove thermal energy as it propagates through the block from bottom to top to be sunk to the thermal transfer plate 30.

Although the present invention has been described above in terms of particular embodiments illustrated in the several figures of the drawing, it will be appreciated that other configurations of fan carrier, flow directing vanes, thermal transfer blocks, heat sink ribs and cover plates may be utilized without deviating from the essence of the present invention. For example, ribs, vanes, or simple grooves or corrugations may be provided in the cover plate 40 in order to increase the surface area thereof. More details of the cover plate can be found in U.S. Pat. No. 6,671,177, entitled “Graphics card apparatus with improved heat dissipation,” which is incorporated herein in its entirety. Also, more than one thermal transfer block may be used to transfer thermal energy from electronic components to the thermal transfer plate 30.

Notwithstanding that the present invention has been described above in terms of several alternative embodiments, it is anticipated that still other alterations and modifications will become apparent to those of ordinary skilled in the art after having read this disclosure. It is therefore intended that such disclosure be considered illustrative and not limiting, and that the appended claims be interpreted to include all such alterations, modifications and embodiments as fall within the true spirit and scope of the invention. 

1. A graphics card apparatus with improved heat dissipation, comprising: a metal block thermally coupled to one or more electronic components of said graphics card apparatus and including a tubing forming a tortuous passage for fluid therewithin, said tubing having an inlet end and an exit end; a radiator including a pipe having an inlet end and an exit end and baffles thermally coupled to said pipe, the inlet end of said pipe being connected to the exit end of said tubing; a pump having first and second ports respectively connected to the inlet end of said tubing and the exit end of said pipe, said pump being operative to circulate coolant through said pipe and said tubing and thereby to transfer thermal energy from said metal block to said radiator; a fan for generating an air flow and a carrier for said fan; and an enclosure surrounding said radiator and metal block, and forming an air passage from said fan to said metal block and thence to said radiator, said enclosure including a generally planar cover plate and a flow director that includes two generally elongated strips and is positioned beneath said cover plate; whereby thermal energy generated by the electronic components is transferred to said metal block and thence to said radiator via said coolant and is ultimately removed from said radiator by an air flow drawn into said air passage.
 2. A graphics card apparatus as recited in claim 1, wherein said cover plate is made of heat conducting material and is operative to sink a portion of thermal energy generated by the electronic components.
 3. A graphics card apparatus as recited in claim 1, wherein said fan carrier includes a base plate having an opening for accommodating said fan and carries a plurality of vanes that are formed on said base plate and are configured to direct an air flow generated by said fan toward said air passage.
 4. A graphics card apparatus as recited in claim 1, further including: a thermal transfer plate thermally coupled to said metal block; a heat sink having one or more radiators that are thermally coupled to said thermal transfer plate; and one or more thermal transfer means for affixation to said electronic components and adapted to be thermally coupled to said heat sink; whereby thermal energy generated by said electronic components is transferred to said heat sink and thermal transfer plate and is removed from said heat sink and thermal transfer plate by an air flow generated by said fan.
 5. A graphics card apparatus as recited in claim 4, further including one or more thermal transfer blocks of heat conductive material having a plurality of passageways extending therethrough for receiving an air flow generated by said fan, each said thermal transfer block being adapted to transfer thermal energy from one of the electronic components to said thermal transfer plate.
 6. A graphics card apparatus as recited in claim 5, wherein each said thermal transfer block includes a generally planar bottom surface for engaging the top surface of one of the electronic components and a top surface adapted to transfer thermal energy to said thermal transfer plate.
 7. A graphics card apparatus as recited in claim 6, further comprising a thermally conductive compound disposed between said thermal transfer plate and said thermal transfer blocks.
 8. A graphics card apparatus as recited in claim 4, further comprising a thermally conductive compound disposed between said thermal transfer plate and said metal block.
 9. A graphics card apparatus as recited in claim 4, further including an insulating plate that prevents an air flow dissipating thermal energy of said heat sink from heating said radiator.
 10. A graphics card apparatus as recited in claim 9, wherein said enclosure includes a generally planar cover plate and a flow director that includes two generally elongated strips and is positioned beneath said cover plate, further including a first plurality of risers disposed proximate at least some of the corners of said insulating plate and adapted to secure said insulating plate in spaced apart relationship to said cover plate.
 11. A graphics card apparatus as recited in claim 10, further including a printed circuit board for mounting said electronic components thereto and a second plurality of risers that are disposed proximate at least some of the corners of said insulating plate and that are adapted to secure said insulating plate in spaced apart relationship to said printed circuit board.
 12. A graphics card apparatus as recited in claim 11, further including a third plurality of risers disposed proximate at least some of the corners of said cover plate and adapted to secure said cover plate in spaced apart relationship to said printed circuit board.
 13. In a graphics card assembly including a printed circuit board with a plurality of heat generating components affixed thereto, and a heat dissipating mechanism also affixed to said printed circuit board for removing thermal energy from the heat generating components, an improved heat dissipating mechanism comprising: a metal block thermally coupled to said components and including a tubing forming a tortuous passage for fluid therewithin, said tubing having an inlet end and an exit end; a radiator including a pipe having an inlet end and an exit end and baffles thermally coupled to said pipe, the inlet end of said pipe being connected to the exit end of said tubing; a pump having a first and second ports respectively connected to the inlet end of said tubing and the exit end of said pipe, said pump being operative to circulate coolant through said pipe and said tubing and thereby to transfer thermal energy from said metal block to said radiator; a fan for generating an air flow and a carrier for said fan; and an enclosure surrounding said radiator and metal block, and forming an air passage from said first fan to said metal block and thence to said radiator, said enclosure including a generally planar cover plate and a flow director that includes two generally elongated strips and is positioned beneath said cover plate; whereby thermal energy generated by the components is transferred to said metal block and thence to said radiator via said coolant and ultimately removed from said radiator by an air flow drawn into said air passage.
 14. In a graphics card assembly as recited in claim 13, further comprising an end plate having a plurality of apertures through which said fan draws air.
 15. In a graphics card assembly as recited in claim 13, wherein said fan carrier includes a base plate having an opening for accommodating said fan and carries a plurality of vanes that are formed on said base plate and are configured to direct an air flow generated by said fan toward said air passage.
 16. In a graphics card assembly as recited in claim 13, further comprising: a thermal transfer plate thermally coupled to said metal block; a heat sink having one or more radiators that are thermally coupled to said thermal transfer plate; and one or more thermal transfer means for affixation to said electronic components and adapted to be thermally coupled to said heat sink; wherein thermal energy generated by said electronic components is transferred to said heat sink and thermal transfer plate and is removed from said heat sink and thermal transfer plate by an air flow generated by said fan.
 17. In a graphics card assembly as recited in claim 16, further including one or more thermal transfer blocks of heat conductive material having a plurality of passageways extending therethrough for receiving an air flow generated by said fan, each said thermal transfer block being adapted to transfer thermal energy from one of the electronic components to said thermal transfer plate.
 18. In a graphics card assembly as recited in claim 17, wherein each said thermal transfer block includes a generally planar bottom surface for engaging the top surface of one of the electronic components and a top surface adapted to transfer thermal energy to said thermal transfer plate. 